94 Mr. N. J. Winch on the Geology of 



oea. It is situated in 55° 32' N. latitude, and is distant from the 

 coast at Beadnel 19 miles. It commands a noble prospect over 

 the surrounding country, and presents a conspicuous sea-mark to 

 vessels coming across the German ocean. Hedgehope and Harthope 

 are subordinate mountains, and the Flodden Hills on the north- 

 eastern side are a still lower group. The latter descend gradually 

 to Millfield plain, where the primary formation terminates in that 

 direction. 



At the foot of the ridge, in some places the usual attendants of 

 primary mountains, the red sandstone and the greywacke slate, 

 are found rising to the day. The former, which bassets out in 

 Roddam Dean, approaches to a conglomerate ; the latter, which 

 appears on both sides of Markington burn, is fine grained in struc- 

 ture ; but the slates there quarried do not stand the action of the air. 



The blocks of stone on the summit of Cheviot consist of flesh- 

 coloured felspar porphyry enclosing crystals of reddish white felspar 

 and occasionally minute crystals of hornblende, resembling in this 

 respect the porphyry of Inverary mentioned by Dr. Garnet and St. 

 Fond. Among the rude masses and blocks which lie scattered by 

 the sides of the Wooler-water, porphyry slate, claystone porphyry, 

 porphyritic syenite, granitic syenite, basalt, and coarse red jasper 

 may be recognised, and the Coquet, Aln, Bremish, and Glen 

 abound with agates. 



One of the beds which produce the latter mineral is a reddish 

 brown amygdaloid with a basis of wacke, the geodes of which are 

 coated, as usual, with green earth. This rock may be observed in 

 situ on the banks of the Coquet a little above Linn-bridge. 



Hornblende rock is by no means uncommon among these hills. 

 Housy crag, which rises above the farm house near Langley ford, 

 in the valley between Hedgehope and Cheviot, is composed of a 



